March 4, 1909] 



NA TURE 



should si^pmcnt if kept for a sufficiently long period, 

 and, further, that it ought to be possible to induce 

 scgment.-ition bv heat, since heat is known to 

 accelerate chemical reactions, but neither of. these 

 results could be obtained. Loeb has suggested, 

 therefore, that the spermatozoon, in conjugating with 

 the ovum, may very possibly remove from the latter 

 a negative catalyser or condition, the presence of 

 which in the ovum somehow inhibits the process of 

 development. Strangely enough, the present work 

 contains no account of Loeb's conclusions in regard to 

 this matter. 



Delage's recent paper (1907) is referred to in a 

 couple of lines, but there is no mention of the fact that 

 his latest method of artificially fertilising sea-urchins' 

 eggs differs radically from those employed by Loeb, 

 and consequently there is no reference to the very 

 important conclusions which Delage deduces from his 

 results. Moreover, we should have expected an 

 allusion to the fact that the symmetry of the sea- 

 urchins which Delage succeeded in rearing was 

 he.\ameral instead of pentameral, an observation 

 which seems to us to have an important bearing on 

 recent .Mendelian research and teaching. Further- 

 more, the statement on another page that Delage has 

 described half the ordinary number of chromosomes 

 for parthenogenetic echinodernis is misleading, since 

 this author says distinctly that in such cases the 

 normal number becomes restored by a process of 

 ■"auto-regulation." 



The account given of fertilisation is followed bv 

 interesting chapters on egg-structure, mitotic ceil 

 division, gastrulation, the mechanism of the develop- 

 ment of differentiation, and the influence of external 

 factors. We have no space left in which to criticise 

 these. .Although we have not refrained from pointing 

 out certain shortcomings, this does not prevent us 

 from congratulating both author and translator on the 

 production of what is, on the whole, a very useful 

 summary of embryogenetic research. 



Francis H. \. Mar.sh.\ll. 



MODERN PHARMACOGNOSY. 

 Handbuch der Pharmakogtwsie. By Prof. A. Tschirch. 

 . Parts ii. to viii. (Leipzig: Chr. Herm. Tauchnitz, 



1908.) Price 2 marks per part. 

 'T^'HE general scheme of this important work on 

 i- pharmacognosy having been described in a pre- 

 vious issue of Nature (vol. Ixxviii., p. 629, October 22, 

 1908), the manner in which the scheme is being carried 

 out may now be examined. 



The bulk of the first four parts, in all about 116 

 pages, is devoted to " pharmacoergasy," that is, the 

 cultivation, collection, and preparation of drugs. 

 Numerous instances, perhaps not very systematically 

 arranged, of the cultivation of drugs in remote ages 

 are cited, and accounts are given of modern attertipts 

 to acclimatise important medicinal plants. The great 

 problem of pharmacoergasy is, according to the author, 

 the determination, not only of the conditions of growth 

 simply, but also of those conditions that most con- 

 duce to the formation of valuable constituents, a 

 NO. 2053, VOL. 80] 



problem which presents a boundless field for investiga- 

 tion. The irrationality of a number of the processes 

 at present in use for drying drugs is indicated, and 

 suggestions made for their improvement. 



The times at which leaves and other organs should 

 be collected are stated in general terms, but'doubt may 

 well be expressed whether these are not in several, 

 perhaps many, instances incorrect ; at least they have 

 not been sufficiently substantiated either by chemical 

 or biochemical assay. To allude to definite instances, 

 it has recently been well established by the physiological 

 experiments of Dixon supporting the assays of 

 Fromnie that the first year's leaves of the foxglove 

 are practically of equal value with the second year's, 

 although Prof. Tschirch would reject them as worth- 

 less. Chemical assay has also deinonstrated the practi- 

 cal equality of the first and second year's henbane 

 leaves, and probably also those of the annual plant were 

 the leaves only of the latter collected and properly 

 dried. Even the best period for the collection of aconite 

 and belladonna cannot yet be regarded as firmly estab- 

 lished. Schroff may well have been the first to indicate 

 the time at which hemlock fruits should be gathered, 

 but the admirable researches of Farr and Wright de- 

 termined the point definitely by analysis. 



In this section enzymes and their influence are con- 

 sidered, though perhaps more emphasis might be laid 

 on their prejudicial action, and on' the means now 

 generally advocated and adopted for obviating it. A 

 most comprehensive list of the plants cultivated in 

 Europe and the United States is included in this part 

 of the work, as well as a chapter on the collection of 

 drugs, well illustrated by a number of photographs. 

 The preparation of drugs is discussed at some length, 

 and consists practically of well-known processes which 

 are commonly given under each drug, but are here 

 collected together. 



Part iv. deals with " pharmacoemporia," or the 

 comtnerce in drugs, a section of pharmacognosy which 

 has until lately been only too much neglected, though 

 of the greatest interest. Here the various routes that 

 commerce between the East and the West has taken 

 from ancient to modern times are briefly, though not 

 too lucidly, traced and explained by three maps. E.\- 

 cellent accounts are given of the drug sales in London, 

 Hamburg, and Amsterdam, those in London being 

 accompanied by several illustrations identical with 

 those first published in the Pharmaccuiical journal by 

 Mr. Heap, an acknowledgment for which has doubt- 

 less escaped the author. Photographs of the most im- 

 portant harbours of the world illustrate this section of 

 the work. 



The commercial varieties of drugs and the pack- 

 ages in which they are exported form the chief 

 subject of part v. In part vi. the advantages and 

 disadvantages of the various pharmacognostical 

 systems of classification that have from time to time 

 been proposed are fully discussed, the author being 

 in favour of one based upon the chemical relation- 

 ships of the chief constituents, though he admits that 

 such a system is at present impracticable, as the 

 constitution of so few of the constituents is sufficiently 

 well known. For all teachers of pharmacognosy the 



